Structural and functional organization of chloroplasts in leaves of Pisum sativum L. under conditions of root hypoxia and iron deficiency
Ladygin, V.G.; Semenova, G.A.
Tsitologiia 45(8): 780-795
2003
ISSN/ISBN: 0041-3771 PMID: 15216630 Document Number: 561365
A combined effect of iron deficiency and root hypoxia on the biochemical composition activity and structure of chloroplasts in pea leaves have been studied. Both factors are shown to affect the accumulation of chlorophyll causing leaf chlorosis. At iron deficiency chlorosis occurs from the top of plant leaves. At root hypoxia chlorosis starts from the lower strata. At a combined action of both factors the destructive effects are summarized. It was established that light-harvesting complexes of photosystems were reduced stronger at iron deficiency, while complexes of reaction centers of photosystem I and photosystem II are lessened at root hypoxia. Nevertheless, even at a combined effect of both factors yellow leaves preserved small amounts of any pigment-protein complexes and their functional activities. The ultrastructure of chloroplasts during leaf chlorosis was gradually reduced. At first, intergranal sites of thylakoids and then granal ones were destroyed, that was typical of iron deficiency. However, even yellow and almost white leaves kept small thylakoids, capable of forming stacking and small grana made of 2-3 thylakoids. It has been concluded that the destructive effects are summarized due to different kinds of action of iron deficiency and root hypoxia on the structure and functioning of leaves at their combined action.